Semiconductor device

ABSTRACT

Semiconductor device includes a pair of substrates ( 1, 2 ) disposed oppositely, semiconductor elements ( 5, 6 ) formed in the substrates ( 1, 2 ), respectively, and having semiconductor circuits ( 3, 4 ) and electrodes ( 7, 8 ), respectively, a wiring conductor ( 9 ) interposed between the electrodes ( 7, 8 ), and a through electrode ( 12 ) extending through one substrate ( 1 ) and connected to the electrode ( 7 ) via the wiring conductor ( 9 ). The other substrate ( 2 ) is disposed laterally of the through electrode ( 12 ). Surface of the through electrode ( 12 ) projecting from the one substrate ( 1 ) and lateral surface of the element ( 6 ) are coated with an insulation material ( 13 ). The through electrode ( 12 ) has one end exposed in a back surface of the one substrate ( 1 ), while other end is positioned flush with a back surface of the other substrate ( 2 ), being exposed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an electrode structure of asemiconductor device. More particularly, the present invention isconcerned with a semiconductor device having a through electrodeincorporated therein and a method of manufacturing the semiconductordevice incorporating the through electrode.

2. Related Art

In the semiconductor device known heretofore the through electrode suchas mentioned above is fabricated by depositing a resist film having anopening on a semiconductor substrate, forming a column of anelectrically conductive material through a plating process and fixing orconsolidating the electrically conductive column by using a resin. Formore particulars, reference may have to be made to Japanese PatentApplication Laid-Open Publication No. 307937/1999 (page 7, FIG. 1).

In the semiconductor device having the through electrode manufactured asmentioned above, the electrode extending through the semiconductorsubstrate, i.e., the through electrode, is electrically isolated orinsulated from the semiconductor substrate by an insulation filminterposed therebetween. For manufacturing the semiconductor device ofthis type, a fine hole of a greater depth is formed with a large aspectratio, whereon an insulation film having a high coating quality isformed on the inner wall of the hole by a chemical vapor deposition(CVD) method while a metal film serving as a cathode in anelectroplating process is deposited with a high coating quality by achemical vapor deposition (CVD) method.

After having filled the hole with a metal by electroplating by employingthe metal film as a cathode, excessive insulation material depositedthrough the CVD process and excessive metal deposited by plating areremoved. Thereafter, the semiconductor substrate is ground from the backside to expose the metal deposited on the bottom portion of the hole.

As is apparent from the above, in manufacturing the conventionalsemiconductor device, it is required to form the hole a large aspectratio in the semiconductor substrate and then form the insulation filmat least on the side or lateral wall of the hole with a high coatingquality without any noticeable defects. In particular, however, it istechnically very difficult to meet such requirement.

Further, the cathode material deposited by plating adheres not only thebottom portion of the hole but also the side wall. Consequently, whenthe metal is buried in the hole through the electroplating process,metal growth occurs not only from the hole bottom but also from the sidewall of the hole. In general, since the metal grows from the side wallportion located at the top portion of the hole at a higher rate becauseof high fluidity, there may arise such unwanted situation that the topportion of the hole is firstly blocked by the metal in the course ofplating, resulting in that the lower portion of the hole remains yet tobe metalized. In order to evade such undesirable situation, it isnecessary to control the metal growth, which control is howeverextremely difficult.

For the reasons mentioned above, great difficulties have beenencountered heretofore in manufacturing the semiconductor deviceincorporating the through electrode, which has presented a greatobstacle to wide-spreading of such semiconductor device. Besides, theyield and the operation reliability of the manufactured semiconductordevice are very low. Additionally, high cost is involved inmanufacturing the semiconductor device.

SUMMARY OF THE INVENTION

In the light of the state of the art described above, it is as an objectof the present invention solve satisfactorily the problem mentionedabove by providing a semiconductor device incorporating a throughelectrode which can be manufactured.

In view of the above and other objects which will become apparent as thedescription proceeds, there is provided according to a general aspect ofthe present invention a semiconductor device which includes first andsecond semiconductor substrates having respective opposite surfacesdisposed in opposition to each other, a first semiconductor elementformed in the opposite surface of the first semiconductor substrate andincluding a first semiconductor circuit and a first electrode, a secondsemiconductor element formed in the opposite surface of the secondsemiconductor substrate and including a second semiconductor circuit anda second electrode, a first wiring conductor layer formed of anelectrically conductive material and interposed between the first andsecond electrodes, and a through electrode extending through the firstsemiconductor substrate and connected to the first and second electrodesthrough the medium of the first wiring conductor layer. In thesemiconductor device described above, the second semiconductor substrateis disposed above the first semiconductor substrate and disposed on alateral side of the through electrode, being distanced therefrom.Lateral surface of the through electrode projecting from the firstsemiconductor substrate and lateral surface of the second semiconductorelement are coated with an insulation material layer. The throughelectrode has one end portion exposed from a back surface of the firstsemiconductor substrate to serve as a first external terminal. Thethrough electrode has the other end portion positioned at a same heightas a back surface of the second semiconductor substrate and exposed fromthe insulation material layer to serve as a second external terminal.

By virtue of the structure of the semiconductor device described above,it is possible to mount or incorporate or package a greater number ofsemiconductor circuits when compared with the conventional semiconductordevice with a substantially same volume.

The above and other objects, features and attendant advantages of thepresent invention will more easily be understood by reading thefollowing description of the preferred embodiments thereof taken, onlyby way of example, in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the course of the description which follows, reference is made to thedrawings, in which:

FIG. 1 is a sectional view showing a semiconductor device according to afirst embodiment of the present invention;

FIG. 2 is a sectional view showing a hitherto known semiconductordevice;

FIG. 3 is a sectional view showing a semiconductor device according to asecond embodiment of the present invention;

FIG. 4 is a view for illustrating a step in a method of manufacturingthe hitherto known semiconductor device;

FIG. 5 is a view for illustrating a step in a method of manufacturingthe hitherto known semiconductor device;

FIG. 6 is a view for illustrating a circuit forming step in a method ofmanufacturing a semiconductor device according to a third embodiment ofthe present invention;

FIG. 7 is a view for illustrating a hole forming step in thesemiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 8 is a view for illustrating an insulation film forming step in thesemiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 9 is a view for illustrating a wiring conductor layer forming stepin the semiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 10 is a view for illustrating a resist pattern forming step in thesemiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 11 is a view for illustrating a through electrode forming step inthe semiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 12 is a view for illustrating an element interconnecting step inthe semiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 13 is a view for illustrating an insulation material coating stepin the semiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 14 is a view for illustrating an insulation coating grinding stepin the semiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 15 is a view for illustrating a back surface grinding step in thesemiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 16 is a view for illustrating a substrate back surface etching stepin the semiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 17 is a view for illustrating a step of etching a bottom portion ofa through electrode in the semiconductor device manufacturing methodaccording to the third embodiment of the present invention;

FIG. 18 is a view for illustrating a supporting member removing step inthe semiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 19 is a view for illustrating a reinforcing step in thesemiconductor device manufacturing method according to the thirdembodiment of the present invention;

FIG. 20 is a sectional view showing a semiconductor device according toa fourth embodiment of the present invention;

FIG. 21 is a sectional view showing a version of the semiconductordevice according to the fourth embodiment of the present invention;

FIG. 22 is a view for illustrating a step of forming a firstsemiconductor circuit in a semiconductor device manufacturing methodaccording to a fifth embodiment of the present invention;

FIG. 23 is a view for illustrating an insulation film/resist depositionstep in the semiconductor device manufacturing method according to thefifth embodiment of the present invention;

FIG. 24 is a view for illustrating a hole forming step in thesemiconductor device manufacturing method according to the fifthembodiment of the present invention;

FIG. 25 is a view for illustrating a second insulation film depositionstep in the semiconductor device manufacturing method according to afifth embodiment of the present invention;

FIG. 26 is a view for illustrating a metal layer plating step in thesemiconductor device manufacturing method according to the fifthembodiment of the present invention;

FIG. 27 is a view for illustrating a metal layer polishing step in thesemiconductor device manufacturing method according to the fifthembodiment of the present invention;

FIG. 28 is a view for illustrating a photoresist pattern forming step inthe semiconductor device manufacturing method according to the fifthembodiment of the present invention;

FIG. 29 is a sectional view showing a semiconductor device according toa sixth embodiment of the present invention;

FIG. 30 is a view for illustrating a substrate back surface grindingstep in a method of manufacturing a semiconductor device according to aseventh embodiment of the present invention;

FIG. 31 is a view for illustrating an electroplating step of forming aback surface insulation film in the semiconductor device manufacturingmethod according to the seventh embodiment of the present invention;

FIG. 32 is a view for illustrating a through electrode bottom exposingstep in the semiconductor device manufacturing method according to theseventh embodiment of the present invention;

FIG. 33 is a sectional view showing a semiconductor device according toan eighth embodiment of the present invention;

FIG. 34 is a view for illustrating a through electrode exposing step ina semiconductor device manufacturing method according to a ninthembodiment of the present invention;

FIG. 35 is a view for illustrating a step of forming a second protrudingelectrode by plating in the semiconductor device manufacturing methodaccording to the ninth embodiment of the present invention;

FIG. 36 is a view for illustrating a step of exposing a wiring conductorlayer at a hole bottom in the semiconductor device manufacturing methodaccording to the ninth embodiment of the present invention;

FIG. 37 is a view for illustrating a first semiconductor substrateetching step in the semiconductor device manufacturing method accordingto the ninth embodiment of the present invention;

FIG. 38 is a view for illustrating a through electrode bottom portionetching step in a semiconductor device manufacturing method according toa tenth embodiment of the present invention;

FIG. 39 is a view for illustrating a step of forming a first protrudingelectrode by plating in the semiconductor device manufacturing methodaccording to the tenth embodiment of the present invention;

FIG. 40 is a view for illustrating a step similar to that shown in FIG.38 in the semiconductor device manufacturing method according to aversion of the tenth embodiment of the present invention;

FIG. 41 is a view for illustrating a step similar to that shown in FIG.39 according to the version of the tenth embodiment of the presentinvention;

FIG. 42 is a sectional view showing a semiconductor device according toan eleventh embodiment of the present invention;

FIG. 43 is a sectional view showing a semiconductor device according toa twelfth embodiment of the present invention;

FIG. 44 is a sectional view showing a semiconductor device according toa thirteenth embodiment of the present invention;

FIG. 45 is a sectional view showing a modification of the semiconductordevice according to the thirteenth embodiment of the present invention;

FIG. 46 is a sectional view showing a semiconductor device according toa fourteenth embodiment of the present invention;

FIG. 47 is a sectional view showing a modification of the semiconductordevice according to the fourteenth embodiment of the present invention;

FIG. 48 is a sectional view showing another modification of thesemiconductor device according to the fourteenth embodiment of thepresent invention;

FIG. 49 is a sectional view showing still another modification of thesemiconductor device according to the fourteenth embodiment of thepresent invention;

FIG. 50 is a sectional view showing a semiconductor device according toa fifteenth embodiment of the present invention;

FIG. 51 is a sectional view showing a modification of the semiconductordevice according to the fifteenth embodiment of the present invention;

FIG. 52 is a sectional view showing another modification of thesemiconductor device according to the fifteenth embodiment of thepresent invention;

FIG. 53 is a sectional view showing still another modification of thesemiconductor device according to the fifteenth embodiment of thepresent invention;

FIG. 54 is a sectional view showing yet another modification of thesemiconductor device according to the fifteenth embodiment of thepresent invention;

FIG. 55 is a sectional view showing a further modification of thesemiconductor device according to the fifteenth embodiment of thepresent invention;

FIG. 56 is a view for illustrating a resist pattern deposition step in asemiconductor device manufacturing method according to a sixteenthembodiment of the present invention;

FIG. 57 is a view for illustrating a through electrode forming step inthe semiconductor device manufacturing method according to the sixteenthembodiment of the present invention;

FIG. 58 is a view for illustrating a second semiconductor elementconnecting or mounting step in the semiconductor device manufacturingmethod according to the sixteenth embodiment of the present invention;

FIG. 59 is a view for illustrating an insulation material coating andgrinding step in the semiconductor device manufacturing method accordingto the sixteenth embodiment of the present invention;

FIG. 60 is a view for illustrating a second semiconductor elementmounting step in a semiconductor device manufacturing method accordingto a seventeenth embodiment of the present invention;

FIG. 61 is a view for illustrating an insulation material coating stepin the semiconductor device manufacturing method according to theseventeenth embodiment of the present invention;

FIG. 62 is a view for illustrating a step of forming a through electrodeby electroplating in the semiconductor device manufacturing methodaccording to the seventeenth embodiment of the present invention;

FIG. 63 is a view for illustrating a bump electrode forming step in thesemiconductor device manufacturing method according to the seventeenthembodiment of the present invention;

FIG. 64 is a view for illustrating a step of exposing a top portion of athrough electrode in a semiconductor device manufacturing methodaccording to an eighteenth embodiment of the present invention;

FIG. 65 is a view for illustrating an insulation film forming step inthe semiconductor device manufacturing method according to theeighteenth embodiment of the present invention;

FIG. 66 is a view for illustrating a step of removing partially theinsulation film at the top portion of the through electrode in thesemiconductor device manufacturing method according to the eighteenthembodiment of the present invention;

FIG. 67 is a sectional view showing a semiconductor device according toa nineteenth embodiment of the present invention;

FIG. 68 is a sectional view showing an SOI (Silicon On Insulator)substrate employed in a semiconductor device manufacturing methodaccording to the nineteenth embodiment of the invention;

FIG. 69 is a view for illustrating a step of forming an insulationlayer, a hole and a wiring conductor layer in the semiconductor devicemanufacturing method according to the nineteenth embodiment of thepresent invention;

FIG. 70 is a view for illustrating a through electrode forming step inthe semiconductor device manufacturing method according to thenineteenth embodiment of the present invention;

FIG. 71 is a view for illustrating a bump electrode forming step in thesemiconductor device manufacturing method according to the nineteenthembodiment of the present invention;

FIG. 72 is a view for illustrating a semiconductor substrate matrixetching process in the semiconductor device manufacturing methodaccording to the nineteenth embodiment of the present invention;

FIG. 73 is a sectional view showing a semiconductor device according toa twentieth embodiment of the present invention;

FIG. 74 is a sectional view showing a semiconductor device according toa twenty-first embodiment of the present invention;

FIG. 75 is a sectional view showing a modification of the semiconductordevice according to the twenty-first embodiment of the presentinvention;

FIG. 76 is a sectional view showing a semiconductor device according toa twenty-second embodiment of the present invention;

FIG. 77 is a sectional view showing a modification of the semiconductordevice according to the twenty-second embodiment of the presentinvention;

FIG. 78 is a sectional view showing a semiconductor device according toa twenty-third embodiment of the present invention;

FIG. 79 is a sectional view showing a modification of the semiconductordevice according to the twenty-third embodiment of the presentinvention;

FIG. 80 is a sectional view showing a semiconductor device according toa twenty-fourth embodiment of the present invention;

FIG. 81 is a sectional view showing a modification of the semiconductordevice according to the twenty-fourth embodiment of the presentinvention;

FIG. 82 is a view for illustrating a step involved in a semiconductordevice manufacturing method according to a twenty-fifth embodiment ofthe present invention;

FIG. 83 is a view for illustrating another step involved in thesemiconductor device manufacturing method according to the twenty-fifthembodiment of the present invention;

FIG. 84 is a view for illustrating yet another step involved in thesemiconductor device manufacturing method according to the twenty-fifthembodiment of the present invention;

FIG. 85 is a view for illustrating still another step involved in thesemiconductor device manufacturing method according to the twenty-fifthembodiment of the present invention;

FIG. 86 is a view for illustrating a further step involved in thesemiconductor device manufacturing method according to the twenty-fifthembodiment of the present invention;

FIG. 87 is a sectional view showing a stack type semiconductor deviceaccording to a twenty-sixth embodiment of the present invention;

FIG. 88 is a sectional view showing a planar array type semiconductordevice according to a twenty-seventh embodiment of the presentinvention;

FIG. 89 is a sectional view showing another planar type semiconductordevice according to the twenty-seventh embodiment of the presentinvention;

FIG. 90 is a sectional view showing a composite type semiconductordevice according to a twenty-eighth embodiment of the present invention;

FIG. 91 is a sectional view showing a composite type semiconductordevice according to a twenty-ninth embodiment of the present invention;

FIG. 92 is a sectional view showing a semiconductor device according toa thirtieth embodiment of the present invention;

FIG. 93 is a view for illustrating a plating step which can be adoptedin the semiconductor device manufacturing method according to theeighteenth embodiment of the invention; and

FIG. 94 is a view for illustrating a plating step which can be adoptedin the semiconductor device manufacturing method according to theeighteenth embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in detail in conjunction withwhat is presently considered as preferred or typical embodiments thereofby reference to the drawings. In the following description, it is to beunderstood that such terms as “top”, “bottom”, “back”, “vertical” andthe like are words of convenience and are not to be construed aslimiting terms.

Embodiment 1

FIG. 1 is a sectional view showing a semiconductor device according to afirst embodiment of the present invention, and FIG. 2 is a sectionalview showing a semiconductor device known heretofore.

Referring to FIG. 1, a first semiconductor circuit 3 is formed in afirst semiconductor substrate 1. Further, a first electrode (or group ofelectrodes) 7 is formed at a location inside of the first semiconductorcircuit 3 or in a peripheral portion thereof.

A second semiconductor circuit 4 is formed in a second semiconductorsubstrate 2, and a second electrode (or group of electrodes) 8 is formedin the second semiconductor circuit 4 at a predetermined positionthereof.

A first semiconductor element 5 which includes the first semiconductorcircuit 3 formed in the first semiconductor substrate 1 on one hand anda second semiconductor element 6 which includes the second semiconductorcircuit 4 formed in the second semiconductor substrate 6 on the otherhand are disposed such that the surfaces in which the firstsemiconductor circuit 3 and the second semiconductor circuit 4 areformed, respectively, face oppositely to each other, wherein the firstsemiconductor element 5 and the second semiconductor element 6 areinterconnected through the medium of the first electrode 7 and thesecond electrode 8.

Further, a column-like through electrode 12 is formed, being exposedfrom a surface (back surface) of the first semiconductor element 5 whichsurface is located oppositely to the surface in which the firstsemiconductor circuit 3 is formed and extending vertically toward thesecond semiconductor substrate to reach a surface which is located atthe side opposite to the surface in which the second semiconductorcircuit 4 of the second semiconductor element 6 is formed.

The through electrode 12 has one end portion exposed from the firstsemiconductor substrate 1 to serve as a first external terminal 10 usedfor connection to an external device or equipment, whereas the other endportion of the through electrode 12 is exposed from the surface whichlies in a plane substantially flush with the surface of the secondsemiconductor element 6 formed in the second semiconductor substrate 2and which is located oppositely to the surface in which the secondsemiconductor circuit 4 is formed, to serve as a second externalterminal 11 for connection to an external device or equipment.

A wiring conductor layer 9 for the first external terminal 10 is formedon the main surface of the first semiconductor substrate 1 and has oneend portion connected to the through electrode 12 with the other endportion thereof being connected to one of the first and secondelectrodes 7 and 8 on the first semiconductor substrate 1.

Further, the surface exclusive of the back surfaces of the first andsecond semiconductor substrates 1 and 2 located oppositely to thesurfaces in which the semiconductor circuits 3 and 4 are formed,respectively, the top surface (the second external terminal 11) of thethrough electrode 12 which lies in a plane extending substantially inflush with the surface of the second semiconductor substrate 2 and thelateral surface of the first semiconductor substrate 1 is coated with aninsulation material 13.

Incidentally, in FIG. 1, reference numeral 30 denotes an insulationfilm.

Turning to FIG. 2 which shows the conventional semiconductor deviceknown heretofore, one semiconductor circuit 22 is formed in thesemiconductor substrate 21, wherein the top and bottom surfaces of thesemiconductor substrate 21 are coated with insulation films 23,respectively. A through electrode 12 extends through the semiconductorsubstrate 21 and has both exposed end portions which protrude from thesemiconductor substrate 21 to form electrodes 24, respectively.Incidentally, in FIG. 2, reference numeral 9 denotes a wiring conductorlayer.

As is apparent from the above description, in the semiconductor deviceaccording to the instant embodiment of the present invention, abouttwice as many semiconductor circuits can be implemented with asubstantially same volume as the conventional semiconductor devicehaving the similar through electrode.

Embodiment 2

FIG. 3 is a sectional view showing a semiconductor device according to asecond embodiment of the present invention. In this figure, theconstituents or components similar to those described previously inconjunction with the first embodiment of the invention by reference toFIG. 1 are denoted by like reference symbols, and repeated descriptionin detail of these components will be omitted.

In the case of the semiconductor device according to the firstembodiment of the invention, the first semiconductor element 5 and thesecond semiconductor element 6 are interconnected through the firstelectrode 7 and the second electrode 8 which are directly contacted witheach other. By contrast, in the semiconductor device according to theinstant embodiment of the invention, the first semiconductor element 5and the second semiconductor element 6 are connected to each otherthrough a bump electrode 20 formed between the first electrode 7 and thesecond electrode 8, as can clearly be seen in FIG. 3.

By adopting the connecting structure described above, interconnection ofthe first semiconductor element 5 and the second semiconductor element 6can be realized with ease.

Further, in the semiconductor device now under consideration, the firstsemiconductor element 5 and the bump electrode 20 can be interconnectedby making use of a portion of the wiring conductor layer 9 connected tothe through electrode 12.

In this conjunction, it is to be added that the bump electrode 20 may beformed on the side of the first semiconductor substrate 1 or on the sideof the second semiconductor substrate 2. Alternatively, the bumpelectrode 20 may be formed on both the first semiconductor substrate 1and the second semiconductor substrate 2.

Embodiment 3

A third embodiment of the present invention is directed to a method ofmanufacturing the semiconductor devices according to the first and thesecond embodiments of the invention. FIGS. 4 and 5 are views forillustrating processes or steps involved in manufacturing theconventional semiconductor device known heretofore. FIGS. 6 to 19 areviews for illustrating steps or processes involved in the semiconductordevice manufacturing method according to the third embodiment of theinvention. In FIGS. 4 to 19, the constituents or components similar tothose described previously by reference to FIGS. 1 to 3 are denoted bylike reference symbols, and repeated description in detail of thesecomponents will be omitted.

When the through electrode is formed in the conventional semiconductordevice such as shown in FIG. 2, a deep hole 25 having a high aspectratio is formed in a semiconductor substrate 21, and an insulation film26 is formed on the inner surface of the hole 25, which is then followedby a step in which the insulation film 26 is coated with a matrix metallayer 27 for plating, as shown in FIG. 4.

Subsequently, the hole 25 is filled with a metal through a platingprocess to thereby form the through electrode 12 mentioned previously byreference to FIG. 2, as shown in FIG. 5.

Now, description will turn to a method of manufacturing thesemiconductor device having the through electrode 12 according to theinvention.

At first, in a step shown in FIG. 6, the first semiconductor circuit 3including a connecting terminal portion is formed in the firstsemiconductor substrate 1 of p- or n-type having a predeterminedelectric resistivity or resistance.

In succession, in a step shown in FIG. 7, a hole of a predetermineddepth is formed in the first semiconductor substrate 1 at a locationadjacent to the peripheral portion of the first semiconductor circuit 3.

In this conjunction, the depth of the hole formed in the firstsemiconductor substrate 1 is so selected that it is greater than thethickness which can effectively ensure operation of the semiconductorelement and that mechanical damage which the first semiconductorsubstrate 1 may undergo during a process or step of machining the firstsemiconductor substrate (described later on) does not practically affectthe operative layer (i.e., active layer). By way of example, the depthof the hole may be selected on the order of 10 μm or more.

When the depth of the hole is selected to be excessively great uponformation of the hole in the first semiconductor substrate 1, variousdifficulties will be encountered. To evade such difficulties, the holeshould be formed as shallow as possible with the aspect ratio beingselected in a range of about 1 (one) to 2. By way of example, when thehole diameter is selected on the order of 10 μm from the practicalstandpoint, then the depth of the hole or the thickness of the firstsemiconductor device, to say in another way, should preferably beselected to be in the range of about 10 to 20 μm, i.e., not greater than20 μm, by taking into account the aspect ratio mentioned above.

Subsequently, in a step shown in FIG. 8, an insulation film (e.g. SiO₂)30 is deposited on the first semiconductor substrate. In succession,those portions of the insulation film 30 which are deposited on thebottom of the hole formed in the step shown in FIG. 7 and the connectingterminal portion formed in the first semiconductor circuit 3 at apredetermined position are removed by etching.

Next, in a step shown in FIG. 9, a metal film 9 is deposited in a mannerillustrated in the figure. This metal film 9 serves as the matrix forthe plating process which will be described hereinafter. In succession,the metal film 9 is processed to thereby form the wiring conductorpattern (which may also be referred to as the connecting conductor andwiring conductor layer). The metal film 9 is also formed on the bottomof the hole from which the insulation film 30 has been removed and thelateral wall of the hole.

In a next step shown in FIG. 10, a photoresist layer 31 is applied,whereon a photoresist pattern (also referred to as the resist pattern31) of a predetermined thickness in which the top portion of the holeformed in the step shown in FIG. 7 is opened is formed through aphotoengraving process.

In that case, the thickness of the photoresist pattern 31 should be soselected as to be slightly greater than the height of the column-likethrough electrode 12 which is subsequently to be formed by plating. Byway of example, the thickness of the photoresist pattern 31 may be in arange of about 50 μm to 100 μm.

In succession, in a step shown in FIG. 11, a metal such as Cu is buriedwithin the opening of the resist pattern 31 by a plating process withthe first semiconductor substrate 1 being used as a cathode by takingadvantage of the electrical conductivity of the substrate 1.

In that case, a metallic material suited as the matrix for the metalplating such as Cu is deposited at least on the outermost surface of theconnecting conductor layer 9 formed in the step shown in FIG. 9.

By the way, the second semiconductor element 6 which includes the secondsemiconductor circuit 4 formed in the second semiconductor substrate 2and the bump electrode 20 is prepared in advance as the discreteelement, as shown in FIG. 12.

The photoresist 31 formed in the step shown in FIG. 10 is removed,whereon the first semiconductor element 5 including the firstsemiconductor circuit 3 formed in the first semiconductor substrate 1 onone hand and the second semiconductor element 6 including the secondsemiconductor circuit 4 formed in the second semiconductor substrate 2on the other hand are positionally aligned with each other so that thesurfaces in which the circuits 3 and 4 are formed, respectively, face inopposition to each other. Subsequently, the first semiconductor element5 and the second semiconductor element 6 are connected to each other bythe bump electrode 20 interposed therebetween.

In that case, the second semiconductor element 6 is disposed on theinner side of the column formed by plating to serve as the throughelectrode 12. The thickness of the second semiconductor element 6 may begreater than the height (thickness) of the column 12 formed by plating.By way of example, the thickness of the second semiconductor element 6may be in the range of 500 μm to 700 μm which is substantially ten timesas great as the height of the column 12 formed by plating.

Subsequently, in a step shown in FIG. 13, the second semiconductorelement 6 and the column formed by plating on the first semiconductorsubstrate 1 to serve as the through electrode 12 are coated with aninsulation material 13 such as an epoxy resin which initially exhibits ahigh fluidity and which can easily be hardened after curing so that thesecond semiconductor element 6 and the through electrode 12 are allembedded in a mass of the insulation material 13.

In a step shown in FIG. 14, the insulation material (resin) 13 isremoved by grinding from the surface in which the second semiconductorelement 6 is formed until the top portion of the through electrode (topportion of the column formed by metal plating) 12 is exposed.

In that case, since the second semiconductor element 6 has a greaterthickness than the height of the column 12, the back surface of thesecond semiconductor element 6 is also exposed.

In a step shown in FIG. 15, a supporting member 32 is bonded to theground and exposed surface of the second semiconductor element 6 with anadhesive layer 33 interposed therebetween. In succession, the backsurface of the first semiconductor substrate 1 (i.e., the surfacelocated oppositely to the surface in which the first semiconductorcircuit 3 is formed) is ground until the back surface of the conductorlayer 9 deposited on the bottom of the through electrode or the holetherefor is exposed.

In a step shown in FIG. 16, semiconductor substrate material of thefirst semiconductor substrate 1 itself is partially etched away by apredetermined amount in order to eliminate those portions of the backsurface of the first semiconductor substrate 1 which are injured by themachine grinding, as occasion requires.

Additionally, in a step shown in FIG. 17, the metal layer 9 deposited atthe bottom of the through electrode or the very bottom portion of thethrough electrode itself is partially etched away by a predeterminedamount with a view to eliminating the injuries taken place in themachine grinding, as the case may be.

In this conjunction, it should however be mentioned that either theetching of the first semiconductor substrate 1 or that of the bottomportion of the through electrode or both of them may be spared. Ofcourse, the sequential order of the etching processes mentioned abovecan be interchanged. The bottom of the through electrode can be used asthe terminal for external connection.

Finally, in a step shown in FIG. 18, the adhesive layer 33 and thesupporting member 32 are stripped off. Thus, the structure of thesemiconductor device having the through electrode such as describedpreviously by reference to FIG. 3 can be realized.

At this juncture, it is to be added that the height of the throughelectrode 12 as measured from the first semiconductor substrate 1 shouldpreferably be determined by selecting the aspect ratio to be small.However, when the aspect ratio is excessively small, the overallthickness of the semiconductor substrates (combination of the firstsemiconductor substrate 1 and the second semiconductor substrate 2) isdecreased, which will result in that the bending strength or rigidity ofthe composite semiconductor substrate will become lowered. Under thecircumstances, the overall thickness of the semiconductor substratesshould preferably be on the order of 100 μm or less on the conditionthat the maximum thickness of the layer of the plated metal buried inthe hole or opening formed in the photoresist layer 31 deposited in athickness appropriate from the practical viewpoint is in a range of 50μm to 100 μm.

FIG. 19 is a view illustrating a modification of the process describedabove. More specifically, in precedence to the coating with theinsulation material 13 described in conjunction with the step shown inFIG. 13, the first semiconductor substrate 1, the second semiconductorsubstrate 2 and the through electrode 12 are precoated with anon-conductive paste (NCP) and subsequently they are coated with theinsulation material 13 such as a resin after flip chip bonding (FCB)with a view to enhancing the strength and reliability by employing thenon-conductive paste (NCP).

In that case, a non-conductive film (NCF), an anisotropic conductivepaste (ACP) or an anisotropic conductive film (ACF) may be employed inplace of the non-conductive paste (NCP), substantially to the sameeffect.

In the conventional semiconductor device manufacturing process,difficulty has been encountered in forming the through electrode withregards to etching of the hole 25 having a great depth and a largeaspect ratio, deposition of the insulation film 26 on the hole 25 withan acceptable coating quality and deposition of the matrix metal 27 forplating.

Besides, when the hole 25 is deep, the hole burying plating processwhich is not accompanied with formation of cavities is difficult to becarried out. More specifically, since metal growth will occur on thelateral wall of the hole as well, cavity is easily produced at alocation such as a top portion of the hole where the fluidity of theplating solution is high and where electrolysis is likely to occurconcentratively. For this reason, it has been difficult to bury the holeby plating while suppressing formation of the cavity or cavities.

By contrast, in the manufacture of the semiconductor device having thethrough electrode according to the method of the invention whichincludes the processes or steps described above, there arises nonecessity of resorting to the techniques for forming the deep hole forformation of the through electrode, forming the insulation film of highcoating susceptibility over the lateral wall of the hole, and forsuppressing occurrence of the cavity at or around the center portion ofthe hole due to high plating rate on the hole wall at the top portionthereof.

More specifically, according to the teachings of the present inventionincarnated in the instant embodiment, the hole of a small aspect ratiois formed, while the through electrode is formed only through theelectroplating from the bottom of the hole. Thereafter, the surroundingsurface of the through electrode is coated with the insulation material.Thus, it is unnecessary to deposit the insulation film on the majorportion of the lateral wall of the electrode where the coating isdifficult. Further, it is not required to deposit on the lateral wall ofthe hole the metal film destined to serve as the cathode for theelectroplating. By virtue of these features, the through electrode canbe formed with ease without being accompanied with any cavity formation.

Further, it should be added that according to the teachings of theinvention incarnated in the instant embodiment thereof, thesemiconductor device can easily be manufactured with an enhancedintegration density approximately twice as high as that of thesemiconductor device known heretofore.

Embodiment 4

FIGS. 20 and 21 are sectional views showing semiconductor devicesaccording to a fourth embodiment of the present invention. In thesefigures, the constituents or components similar to those describedpreviously in conjunction with the first to third embodiments of theinvention by reference to FIGS. 1 to 19 are denoted by like referencesymbols, and repeated description in detail of these components will beomitted.

Referring to FIGS. 20 and 21, in the semiconductor device according tothe instant embodiment of the invention, a first additional externalterminal 44 is additionally provided in a region of the firstsemiconductor substrate 1 facing oppositely to the second semiconductorelement 6 so as to extend through the first semiconductor substrate 1.

In the semiconductor device shown in FIG. 20, the first additionalexternal terminal 44 is connected to the second semiconductor element 6through the medium of the bump electrode 20. In the semiconductor deviceshown in FIG. 21, the first additional external terminal 44 is connectedto the first semiconductor circuit 3 of the first semiconductor element5 by way of the connecting conductor 9.

As can easily be appreciated, in the semiconductor devices according tothe instant embodiment of the invention, the first and secondsemiconductor circuits 3 and 4 can be connected in various forms throughthe medium of the first external terminal 10 and the first additionalexternal terminal 44, whereby the degree of freedom in design of thesemiconductor device can significantly be enhanced.

Embodiment 5

A fifth embodiment of the present invention is directed to a method ofmanufacturing the semiconductor devices according to the fourthembodiment of the invention. FIGS. 22 to 28 are views for illustratingsteps or processes involved in the semiconductor device manufacturingmethod according to the fifth embodiment of the invention. In FIGS. 22to 28, the constituents or components similar to those describedpreviously in conjunction with the first to fourth embodiments of theinvention (refer to FIGS. 1 to 21) are denoted by like referencesymbols, and repeated description in detail of these components will beomitted.

In a step shown in FIG. 22, first semiconductor circuits 3 are formed inthe p- or n-type substrate having a predetermined resistance. In thisconjunction, it is to be mentioned that the regions in which the firstsemiconductor circuits 3 are to be formed are previously covered withinsulation films 30 except for the locations where the holes and theconnecting portions (electrodes) are to be formed.

In a step shown in FIG. 23, first insulation films 40 are additionallydeposited over the top surfaces of the insulation films 30, whereon aphotoresist film 31 is formed on the first insulation films 40 in apredetermined thickness. Subsequently, the portions for forming holesare removed.

In a step shown in FIG. 24, holes of a predetermined depth are formed inthe first semiconductor substrate 1 at two locations, respectively, byusing the first insulation film 40 as the mask.

Substantially, in a step shown in FIG. 25, a second insulation film 41is deposited on the top surface of the first insulation film 40.Further, all the insulation films formed on the bottom of the holes andthe connecting portions (electrodes) formed at the predeterminedlocations of the first semiconductor circuits 3 and additionally thesecond insulation film 41 on the portion which is to form the connectingconductor 9 are all removed.

In a step shown in FIG. 26, the metal film 9 which is to serve as thematrix for the plating is deposited on the top surface of the firstsemiconductor substrate 1. In addition, the top surface of the firstsemiconductor substrate 1 inclusive of the hole, the connecting portionand the wiring conductor layer 9 is electroplated to form a plated metallayer 42 by making use of the metal film 9 or the first semiconductorsubstrate 1 as the cathode.

Next, in a step shown in FIG. 27, the plated metal layer 42 formed onthe whole surface is ground by a chemical-mechanical polishing (CMP)until the second insulation film 41 is exposed.

In that case, the metal layers deposited on the hole, the connectingportion and the wiring conductor layer 9 formed concavely due to thesecond insulation film 41 remain unremoved.

In a step shown in FIG. 28, a resist pattern 31 in which the throughelectrode forming portion is opened is formed on the ground or polishedsurface, whereon a metal is buried into the opening portion of theresist pattern 31 through electroplating process with the firstsemiconductor substrate 1 being used as the cathode.

Subsequently, the first semiconductor substrate 1 and the secondsemiconductor element 6 are interconnected to form the semiconductordevice(s) having the through electrode 12 as shown in FIGS. 20 and 21through the processes similar to those described hereinbefore byreference to FIGS. 12 to 18.

In this way, the through electrode can be formed without resorting tothe technique or process which is difficult to carry out as in the caseof the prior art. Further, the semiconductor device having a pluralityof external terminals can easily be fabricated with approximately twiceas large integration density as the conventional semiconductor device.

Incidentally, although the foregoing description has been made that thepresent invention is applied to a so-called dual machine, it should beappreciated that the semiconductor device of the similar structure canbe fabricated by adopting the metal film pattern formation based on thephotoetching and the hole burying electroplating.

Embodiment 6

FIG. 29 is a sectional view showing a semiconductor device according toa sixth embodiment of the present invention. In this figure, theconstituents or components similar to those described previously inconjunction with the first to fifth embodiments of the invention byreference to FIGS. 1 to 28 are denoted by like reference symbols, andrepeated description in detail of these components will be omitted.

Referring to FIG. 29, in the semiconductor device according to theinstant embodiment of the invention, an insulation film (back-surfaceinsulation film) 60 is deposited on the surface of the firstsemiconductor substrate 1 in which the first external terminal 10 isformed. By virtue of this structure, electrical/chemical stability ofthe semiconductor device can be improved, whereby reliability thereofcan be enhanced.

Embodiment 7

A seventh embodiment of the present invention is directed to a method offorming the back-surface insulation film 60 in the semiconductor deviceaccording to the sixth embodiment of the present invention. FIGS. 30 to32 are views for illustrating steps or processes involved in the methodof forming the back-surface insulation film 60 according to the seventhembodiment of the invention. In FIGS. 30 to 32, the constituents orcomponents similar to those described previously in conjunction with thefirst to sixth embodiments of the invention by reference to FIGS. 1 to29 are denoted by like reference symbols, and repeated description indetail of these components will be omitted.

In a step shown in FIG. 30, the semiconductor substrate material itselfis etched away by a predetermined amount in order to eliminate thoseportions of the back surface of the first semiconductor substrate 1which are injured by the machine grinding, as described hereinbefore inconjunction with the step shown in FIG. 16.

Subsequently, in a step shown in FIG. 31, one electrode of a powersupply 72 is electrically connected to the first semiconductor substrate1 of the semiconductor device which is immersed in a solution 71 whilethe other electrode of the power supply 72 is connected to an electrodearray (opposite electrode array) 70 which is disposed in opposition tothe surface of the first semiconductor substrate 1 in which the firstexternal terminal 10 is exposed, to thereby cause an electric current toflow through the first semiconductor substrate 1. Then, only the exposedportion of the first semiconductor substrate 1 itself undergoes anodeoxidation, whereby the back-surface insulation film 60 is formed.

Although it has been described that the electrode array 70 is disposedin opposition to the surface of the first semiconductor substrate 1 inwhich the first external terminal 10 is exposed, the invention is notnecessarily restricted to such disposition.

In a step shown in FIG. 32, the portion of the connecting conductorlayer 9 formed around the first external terminal 10 is removed tothereby expose the bottom portion of the through electrode 12.

In this manner, the back-surface insulation film 60 can be formedrelatively easily and selectively, i.e., only over the exposed portionof the first semiconductor substrate 1 expect the bottom portion of thethrough electrode 12.

As a variation, an insulative organic film can selectively be formedover the exposed surface of the first semiconductor substrate 1 throughan electrodeposition coating process as well.

Further, it goes without saying that such a process can equally beemployed that includes deposition of the insulation film and eliminationof the electrode by etching, as known generally in this art.

Embodiment 8

FIG. 33 is a sectional view showing a semiconductor device according toan eighth embodiment of the present invention. In this figure, thecomponents similar to those described previously in conjunction with thefirst to seventh embodiments of the invention by reference to FIGS. 1 to32 are denoted by like reference symbols, and repeated description indetail of these components will be omitted.

Referring to FIG. 33, in the semiconductor device according to theinstant embodiment of the invention, at least one of the first andsecond external terminals 10 and 11 is provided with a first protrudingelectrode 80 or a second protruding electrode 81 with a view tofacilitating the electrical connection with the external terminal.

Embodiment 9

A ninth embodiment of the present invention is directed to a method offorming the second protruding electrode 81 in the semiconductor deviceaccording to the eighth embodiment of the invention. FIGS. 34 to 37 areviews for illustrating steps or processes involved in the method offorming the second protruding electrode 81 according to the ninthembodiment of the invention. In these figures, the constituents orcomponents similar to those described previously in conjunction with thefirst to eighth embodiments of the invention by reference to FIGS. 1 to33 are denoted by like reference symbols, and repeated description indetail of these components will be omitted.

In a step shown in FIG. 34, the insulation material 13 is removed bygrinding the semiconductor device from the side on which the secondsemiconductor element 6 is mounted until the through electrode 12 isexposed, as described hereinbefore in conjunction with the step shown inFIG. 14.

Subsequently, in a step shown in FIG. 35, the semiconductor device isimmersed in an electroplating solution 90, whereon one terminal of thepower supply 72 is electrically connected to the first semiconductorsubstrate 1 while connecting the other terminal of the power supply 72to an electrode array 70 disposed in opposition to the surface of thesemiconductor device in which the through electrode 12 is exposed,whereon the electroplating is performed on the exposed top portion ofthe through electrode 12 by using the electrode array 70 as anode whileusing the first semiconductor substrate 1 as cathode, to thereby form asecond protruding electrode 81.

Although it has been described above that the electrode array 70 isdisposed in opposition to the surface of the semiconductor device inwhich the through electrode 12 is exposed, the invention is notnecessarily restricted to such disposition.

Next, in a step shown in FIG. 36, a supporting member 32 is bonded tothe semiconductor device on the side at which the second semiconductorelement 6 is located by using an interposed adhesive layer 33, whereonthe grinding process is carried out for removing the substrate materialfrom the back surface of the first semiconductor substrate 1 until theback surface of the wiring conductor layer 9 deposited on the bottom ofthe hole or the bottom of the through electrode 12 is exposed, asdescribed hereinbefore in conjunction with the step shown in FIG. 15.

Subsequently, in a step shown in FIG. 37, substrate material is removedby a predetermined amount from the first semiconductor substrate 1 byetching.

In the stage shown in FIG. 35, the first semiconductor substrate 1 andthe through electrode 12 are electrically short-circuited. Accordingly,by resorting to the electroplating step described above, the protrudingelectrode 81 can easily be formed only on the second external terminal11.

Embodiment 10

A tenth embodiment of the present invention is directed to a method offorming the first protruding electrode 80 in the semiconductor deviceaccording to the eighth embodiment of the present invention. FIGS. 38 to41 are views for illustrating steps or processes involved in the methodof forming the first protruding electrode 80 according to the eighthembodiment of the invention. In FIGS. 38 to 41, the constituents orcomponents similar to those described previously in conjunction with thefirst to ninth embodiments of the invention by reference to FIGS. 1 to37 are denoted by like reference symbols, and repeated description indetail of these components will be omitted.

In a step shown in FIG. 38, the matrix metal layer forming the bottomportion of the through electrode 12 is removed, which is then followedby a step shown in FIG. 39 in which the first protruding electrode 80 isformed only on the metal matrix exposed on the bottom portion of thethrough electrode 12 by an electroless plating in the state in which thesemiconductor device is immersed in an electroless plating solution 91,similarly to the step described hereinbefore by reference to FIG. 15 orFIG. 16.

Subsequently, after the process described hereinbefore by reference toFIG. 37, the matrix metal layer of the bottom portion of the throughelectrode 12 is removed, whereon the first protruding electrode 80 isformed on the exposed bottom portion of the through electrode 12 throughelectroless plating process in a step shown in FIG. 41 similarly to thestep described previously by reference to FIG. 39.

By way of example, when the through electrode 12 is formed of Cu, theprotruding electrode can easily be formed through an electroless nickel(Ni) plating or the like process by taking advantage of the propertythat the electroless-plated film (e.g. Ni) grows selectively only on themetal (Cu) matrix exposed on the bottom portion of the throughelectrode.

Embodiment 11

FIG. 42 is a sectional view showing a semiconductor device of a stacktype according to an eleventh embodiment of the present invention.

Incidentally, in FIG. 42, the parts or components similar to thosedescribed hereinbefore by reference to FIGS. 1 to 41 are denoted by likereference symbols and repeated description in detail thereof is omitted.

The semiconductor device shown in FIG. 42 is implemented in a stackedstructure in which a plurality of semiconductor devices describedheretofore are stacked one to another.

More specifically, in the semiconductor device of the stacked structureshown in FIG. 42, two semiconductor devices are stacked together in thevertical direction with the first protruding electrode 80 and the secondprotruding electrode 81 being contacted to each other.

As can be seen in the figure, there is formed a layer 110 of a resinbetween the surface of the top-side semiconductor device on which thefirst protruding electrode 80 is provided on one hand and the surface ofthe bottom-side semiconductor device on which the second protrudingelectrode 81 is located on the other hand, wherein the first and secondprotruding electrodes 80 and 81 of the top- and bottom-sidesemiconductor devices are positioned in contact with each other.

By stacking a plurality of semiconductor devices in a so-calledlaminated structure as described above, not only the integration densitybut also the operation speed can be increased because the signaltransmission paths can be shortened.

At this juncture, it should be added that the individual semiconductorelements may differ from one another so long as the positions of thethrough electrodes 12 are same.

Further, in the case of the semiconductor device stack shown in FIG. 42,the bump electrodes (fist and second protruding electrodes 80 and 81)are formed on both the top and bottom sides of the semiconductor device.However, the bump electrode may be formed only on one side without anyadverse influence to the operation.

Embodiment 12

FIG. 43 is a sectional view showing a semiconductor device of a stackedtype (also referred to as the integrated semiconductor device stack)according to a twelfth embodiment of the present invention.

Incidentally, in FIG. 43, the parts or components similar to thosedescribed hereinbefore by reference to FIGS. 1 to 42 are denoted by likereference symbols and repeated description in detail thereof is omitted.

In the semiconductor device stack shown in FIG. 43, two semiconductordevices described previously are stacked in the vertical direction withthe respective first protruding electrodes 80 being positioned incontact with each other.

As can be seen in the figure, there is formed a resin layer 110 betweenthe surfaces of the top- and bottom-side semiconductor devices on whichthe first protruding electrodes 80 are provided, respectively, whereinthe first protruding electrodes (80) of the both semiconductor devicesare contacted to each other.

In each of the semiconductor devices of the integrated semiconductordevice stack shown in FIG. 43, the distance between the back surface ofthe first semiconductor substrate 1 and the first semiconductor circuit(activated layer) 3 is short. For this reason, in the case where thesemiconductor device is employed discretely, it is susceptible to theinfluence of external disturbance. Besides, from the mechanicalstandpoint, the semiconductor device is rather feeble. Accordingly, bystacking the semiconductor devices in opposition to each other as shownin FIG. 43, there can also be realized a function for protecting theindividual semiconductor devices.

In that case, the insulation film formed on the back surfaces of thefirst semiconductor substrates in the semiconductor device stack may bespared without incurring degradation in the operation reliability owingto the protecting function mentioned above.

Embodiment 13

FIGS. 44 and 45 are sectional views showing a stack type semiconductordevice according to a thirteenth embodiment of the present invention.

Incidentally, in FIGS. 44 and 45, the parts or components similar tothose described hereinbefore by reference to FIGS. 1 to 43 are denotedby like reference symbols and repeated description in detail thereof isomitted.

In the integrated semiconductor device stack shown in FIG. 44, thesemiconductor devices each equipped with the first additional externalterminal 44 as described hereinbefore in conjunction with the fourthembodiment of the invention are stacked together with the firstprotruding electrodes formed on both the first external terminals andthe first additional external terminals, respectively, beinginterconnected, whereas in the integrated semiconductor device stackshown in FIG. 45, the semiconductor devices are stacked together withthe respective second protruding electrodes 80 being contacted to eachother.

In the integrated semiconductor device stack shown in FIG. 44 in whichthe first semiconductor elements 5 are stacked with the back surfacesthereof being disposed in opposition to each other, as shown in FIG. 44,the number of the terminals can be increased while the signaltransmission paths can be shortened. Thus, the semiconductor devicestack can effectively be employed in such application where high-speedsignal processing on a large scale has to be executed internally of thesemiconductor device stack.

On the other hand, in the semiconductor device stack shown in FIG. 45 inwhich two semiconductor devices are stacked together with the respectivesecond semiconductor elements 6 being disposed in opposition to eachother, there are available a greater number of terminals for externalconnection when compared with the structure shown in FIG. 44. Thus, theintegrated semiconductor device stack shown in FIG. 45 canadvantageously be employed in the application where signal processingshave to be executed on a large scale basis with external devices orequipment.

Embodiment 14

FIGS. 46, 47, 48 and 49 are sectional views showing semiconductordevices according to a fourteenth embodiment of the present invention.

Incidentally, in FIGS. 46 to 49, the constituents or components similarto those described hereinbefore by reference to FIGS. 1 to 45 aredenoted by like reference symbols and repeated description in detailthereof is omitted.

Referring to FIGS. 46 and 47, the back surface of the secondsemiconductor element 6 (back surface of the second semiconductorsubstrate 2) is covered with an insulation material 13. In thesemiconductor device shown in FIG. 46, the back surface of the secondsemiconductor element 6 is coated with the insulation material 13 whichcovers at the same time the lateral surfaces of the through electrode 12and the second semiconductor element 6, respectively. On the other hand,in the semiconductor device shown in FIG. 47, the step of covering thelateral surfaces of the through electrode 12 and the secondsemiconductor element 6 with the insulation material 13 and the step ofcoating the back surface of the second semiconductor element 6 with theinsulation film 140 are carried out separately from each other.

By covering the back surface of the second semiconductor element 6 withthe insulation material (insulation film), not only the electricalstability can be improved but also the chemical and mechanicalwithstanding capability can be enhanced because the insulation material13 in general serves for the protecting function as well, whereby highreliability can be ensured.

Incidentally, in the case where the coating with the insulation materialis carried out separately, as in a case of the semiconductor devicestack shown in FIG. 47, there can be employed same or different types ofinsulation materials, as the case may be.

Further, as shown in FIGS. 48 and 49, the bump electrode (first andsecond protruding electrodes) may be formed on either one or bothsurfaces in the semiconductor devices shown in FIGS. 46 and 47.

Embodiment 15

FIGS. 50, 51, 52, 53, 54 and 55 are sectional views showing,respectively, semiconductor devices according to a fifteenth embodimentof the present invention.

Incidentally, in these figures, the parts or components similar to thosedescribed hereinbefore by reference to FIGS. 1 to 49 are denoted by likereference symbols and repeated description in detail thereof is omitted.

In the semiconductor device of a structure shown in FIG. 50, a wiringconductor layer 150 is formed on the back surface region of the secondsemiconductor element 6 coated with the insulation material 13 in thesemiconductor device according to the fourteenth embodiment of theinvention described hereinbefore. Although one wiring conductor layer150 is shown in FIG. 50, the invention is never restricted thereto. Twoor more wiring conductor layers may be formed with an inter-layerinsulation film being interposed therebetween. A protection film 151 isformed on the top surface of the wiring conductor layer 150 except theportion where the electrode is to be formed, as mentioned below. Thisprotection film 151 may be spared although it depends on the propertiesof the material of the material of the wiring conductor layer 150 asexposed.

Formed at a predetermined location on the top surface of the wiringconductor layer 150 is an electrode (land) 152.

In the semiconductor device shown in FIG. 51, a plurality of portions ofthe wiring conductor layer 150 are used as external terminals byemploying an insulation film pattern 151 in which a plurality oflocations for disposition of electrodes 152 are formed.

Referring to FIGS. 52 to 54, FIGS. 52 to 54, the wiring conductor layer150 is formed on the exposed surface of the insulation material 13coated on the side of the second semiconductor element 6 (FIG. 52).Subsequently, the protection film 151 is formed on the top surface ofthe wiring conductor layer (150) except the location where the electrodeis to be formed (FIG. 53). The electrode 152 is formed at the electrodeforming location, whereon the back surface of the first semiconductorsubstrate 1 is ground and etched, which is then followed by formation ofa bump electrode (first protruding electrode 80) by electroless platingprocess (FIG. 54). Additionally, a solder ball 160 is formed on theelectrode 152, as shown in FIG. 55.

As is apparent from the above, the back surface of the secondsemiconductor element 6 (i.e., exposed surface of the insulationmaterial 13) can effectively be utilized for forming the electrode(s)(external terminal(s)). By virtue of this feature, a large electrode(e.g. 152) can be attached without being limited by the size of theexposed top portion of the through electrode 12.

Further, the degree of freedom in selecting the disposition of theelectrode(s) can be increased. Besides, the number of electrodes (thenumber of external terminals) can be increased as well.

Moreover, not only the integration density can be increased but also thedegree of freedom in design can be enhanced.

It should further be added that although the instant embodiment of theinvention starts from the semiconductor device according to thefourteenth embodiment of the invention (see FIG. 46), the teachings ofthe invention incarnated in the instant embodiment can equally beapplied to the semiconductor device shown in FIG. 47 substantially tothe same advantageous effects.

Embodiment 16

A sixteenth embodiment of the present invention is directed to a methodof manufacturing the semiconductor device shown in FIG. 46 according tothe fourteenth embodiment of the invention. FIGS. 56, 57, 58 and 59 areviews for illustrating steps or processes involved in the semiconductordevice manufacturing method according to the sixteenth embodiment of theinvention. In FIGS. 56 to 59, the constituents or components similar tothose described previously in conjunction with the first to fifteenthembodiments of the invention by reference to refer to FIGS. 1 to 55 aredenoted by like reference symbols, and repeated description in detail ofthese components will be omitted. Further, in the manufacturing methodnow under consideration, the steps same as described hereinbefore byreference to FIGS. 6 to 9 and FIGS. 15 to 18 will be omitted from thefollowing description. Thus, the following description will be directedto the steps corresponding to those described previously by reference toFIGS. 10 to 14.

In a step shown in FIG. 56, a photoresist 31 having a greater thicknessthan that of the second semiconductor element 6 mounted later on isformed with an opening or hole.

In a step shown in FIG. 57, an electrode material is buried in the holeformed in the resist pattern 31 by electroplating with the firstsemiconductor substrate 1 being used as cathode, to thereby form thethrough electrode 12.

In that case, the electrode material is buried up to a height higherthan the second semiconductor element 6 to be subsequently mounted andlower than the thickness of the resist 31.

In a step shown in FIG. 58, the second semiconductor element 6 isconnected to the first semiconductor element 5 with the bump electrode20 being interposed therebetween. The second semiconductor element 6 isformed thin in advance so that the height of the through electrode 12formed by plating exceeds the back surface of the second semiconductorelement 6.

In a step shown in FIG. 59, an insulation material 13 such as a resin,glass or the like is coated and cured. In succession, a grinding processis carried out until the top portion of the through electrode 12 asformed is exposed.

Since the second semiconductor element 6 is formed thinner than theheight of the through electrode 12 formed by plating, the insulationmaterial 13 is deposited not only on the lateral surface of the throughelectrode 12 but also over the back surface of the second semiconductorelement 6.

In this manner, the back surface of the second semiconductor element 6can easily be coated with the insulation material by using intactly thesteps described hereinbefore in conjunction with the third embodiment ofthe invention simply by changing the thickness of the result, platingheight of the through electrode and the thickness of the semiconductorelement to be mounted.

Embodiment 17

A seventeenth embodiment of the present invention is directed to amethod of manufacturing the semiconductor devices shown in FIGS. 46 and48 according to the fourteenth embodiment of the invention. FIGS. 60,61, 62 and 63 are views for illustrating steps or processes involved inthe semiconductor device manufacturing method according to theseventeenth embodiment of the invention. In these figures, theconstituents or components similar to those described previously inconjunction with the first to sixteenth embodiments of the invention byreference to FIGS. 1 to 59 are denoted by like reference symbols, andrepeated description in detail of these components will be omitted.Further, in the manufacturing method now under consideration, the stepssame as described hereinbefore by reference to FIGS. 6 to 9 and FIGS. 15to 18 will be omitted from the following description. Thus, thefollowing description is directed to the steps corresponding to thosedescribed previously by reference to FIGS. 10 to 14.

In a step shown in FIG. 60, the second semiconductor element 6 ground toa predetermined thickness is mounted at a predetermined location byinterposing the bump electrode 20 and the predetermined electrode(second electrode 8).

In succession, in a step shown in FIG. 61, a material forming theinsulation film 13 is applied in a thickness greater than that of thesecond semiconductor element 6. As the material forming the insulationfilm 13, such material as photosensitive polyimide which has initially ahigh fluidity and exhibits photosensitivity after application and whichcan be cured to form a proper insulation layer should preferably be usedso that a desired pattern can be formed by exposure through a mask.

After the second semiconductor element 6 has wholly been covered withthe insulation film 13, a hole is opened through exposure/developmentprocess, which is then followed by a curing process.

In a step shown in FIG. 62, a conductive material is buried into theopened portion through an electroplating process by using the firstsemiconductor substrate 1 as the cathode to thereby form a column(through electrode) 170 of an electrically conductive material on thematrix constituted by the metal film 9 in a height greater than thethickness of the second semiconductor element 6.

In this conjunction, it should be mentioned that the electricallyconductive column 170 may be formed as a bump electrode projectingbeyond the surface of the photosensitive polyimide film 13 through theelectroplating process, as shown in FIG. 63. In that case, the step ofadditionally forming the bump electrode can be spared.

Subsequently, the top portion of the column 170 formed of theelectrically conductive material and serving as the through electrodemay be exposed by grinding the photosensitive polyimide layer 13 fromthe back side of the second semiconductor element 6 so that the topportion of the through electrode 170 lies in a plane flush with thesurface of the photosensitive polyimide layer 13. In that case, thepolyimide film remains as the insulation material 13 on the back surfaceof the second semiconductor element 6 because the second semiconductorelement 6 is thinner than the plated column 170.

As is apparent from the above, the plated column or through electrode170 of the height greater than the thickness of the second semiconductorelement 6 can be formed after the second semiconductor element 6 hasbeen mounted. Owing to this feature, mounting of the secondsemiconductor element 6 and the positional alignment can be muchfacilitated.

Embodiment 18

FIGS. 64, 65 and 66 are views for illustrating steps or processesinvolved in the semiconductor device manufacturing method according toan eighteenth embodiment of the present invention. In these figures, theconstituents or components similar to those described previously inconjunction with the first to seventeenth embodiments of the inventionby reference to FIGS. 1 to 63 are denoted by like reference symbols, andrepeated description in detail of these components will be omitted.Further, description of the steps same as those described previously byreference to FIGS. 6 to 18 is omitted. The steps described below areadded between the step shown in FIG. 14 and the one shown in FIG. 15.

In a step shown in FIG. 64, an insulation material 13 is ground tothereby expose the top portion of the through electrode 12 as describedhereinbefore by reference to FIG. 14.

In succession, in a step shown in FIG. 65, a material 180 is appliedover the surface on the back side of the second semiconductor element 6in a uniform thickness. As the material 180, there may be used such amaterial as photosensitive polyimide which has initially a high fluidityand exhibits photosensitivity after application so that a desiredpattern can be formed by exposure through a mask and which can be curedto form a proper insulation layer.

In a step shown in FIG. 66, when the applied material 180 is theinsulation material having the photosensitivity, the top portion of theelectrode 12 is exposed trough exposure/development process to therebyform the insulation film (180) by heat curing. On the other hand, unlessthe material 180 has no photosensitivity, a photoresist pattern isadditionally applied for carrying out the etching process to expose thetop portion of the through electrode 12.

In this way, there can be formed the insulation film of high quality andhigh reliability.

In the foregoing description of the instant embodiment, it has beenpresumed that photosensitive polyimide is employed as the insulationfilm 180. It should however be appreciated that more fine patterning canbe realized with high reliability by resorting to a deposition processsuch as a chemical vapor deposition (CVD) and a patterning process basedon etching through a photoresist mask which are well known in the art.

Further, a screen printing which is technically of slightly poor inrespect to the fine processing capability can equally be employedwithout difficulty. The screen printing process itself is also atechnique well known in this art. Besides, by applying the processesmentioned above to the formation of the (metal) wiring conductor layer,the inter-layer insulation film and the protection film, there may beformed an additional wiring conductor layer(s) and an additionalexternal terminal(s) on the back surface of the second semiconductorelement 6.

FIGS. 93 and 94 are views for illustrating steps in a semiconductordevice manufacturing method according to the eighteenth embodiment ofthe present invention.

As can be seen in FIGS. 93 and 94, since the first semiconductorsubstrate 1 is electrically coupled to the second semiconductor element6 by way of the through electrode 12 and the bump electrode 20 at leastthrough the grounded potential in common, it is possible to formselectively an insulation film 182 of a material e.g. of polyimideseries on the back surface of the second semiconductor element 6 by amethod similar to the electrodeposition coating.

Further, the insulation film 182 can equally be formed through an anodicoxidation process as well.

Additionally, the process mentioned above can be carried outsimultaneously with the process for forming the insulation film 60 onthe back surface of the first semiconductor element 5 after grinding thefirst semiconductor substrate 1 and stripping off the supporting memberas described hereinbefore in conjunction with the seventh embodiment ofthe invention.

Incidentally, in FIGS. 93 and 94, reference numeral 70 denotes anelectrode array 181 denotes a solution and numeral 72 denotes a powersupply.

Embodiment 19

FIG. 67 is a sectional view showing a semiconductor device according toa nineteenth embodiment of the present invention. FIGS. 68, 69, 70, 71and 72 are views for illustrating steps or processes involved in themethod of manufacturing the semiconductor device according to thenineteenth embodiment. In these figures, the constituents or componentssimilar to those described previously in conjunction with the first toeighteenth embodiments of the invention by reference to FIGS. 1 to 66are denoted by like reference symbols, and repeated description indetail of these components is omitted.

In the semiconductor device shown in FIG. 67, a composite substratewhich is known as the silicon-on-insulator (SOI) substrate (hereinafterreferred to as the SOI substrate) is employed as the first semiconductorsubstrate 1.

The SOI substrate is composed of a semiconductor substrate matrix(semiconductor) 190, an insulation film (buried insulation film) 191deposited on the semiconductor substrate matrix 190 and an extremelythin semiconductor film (activated layer) deposited on the insulationfilm 191.

The method of manufacturing the semiconductor device in which the SOIsubstrate 1 is employed as the first semiconductor substrate 1 issubstantially same as the method described hereinbefore in conjunctionwith the third embodiment of the invention.

Now, description will be directed to the method of manufacturing thesemiconductor device in which the SOI substrate 1 is employed.

In a step shown in FIG. 68, the SOI substrate is employed as the firstsemiconductor substrate (1) and a hole is formed which reaches thesemiconductor substrate matrix 190, extending through the extremely thinsemiconductor film 3 deposited on the SOI substrate and the buriedinsulation film 191.

Subsequently, in a step shown in FIG. 69, an insulation film 30 isdeposited on the top surface of the SOI substrate, whereon theinsulation film 30 is removed from the bottom portion of the hole andthe portion where the electrode is to be formed by etching, which isthen followed by formation of the connecting conductor layer 9,similarly to the steps shown in FIGS. 8 and 9.

In a step shown in FIG. 70, the material for forming the throughelectrode 12 is buried in the opening formed in the resist layer 31through the similar processes described hereinbefore by reference toFIGS. 10 and 11. In that case, since the bottom portion of the holereaches the layer of the semiconductor substrate matrix 190, plating canbe carried out by making use of the semiconductor substrate matrix 190as the electrode.

Subsequently, in a step shown in FIG. 71, the second semiconductorelement 6 is mounted, whereon the insulation material 13 is deposited,which is then followed by the step where the top portion of the throughelectrode 12 is exposed by grinding, similarly to the processesdescribed previously by reference to FIGS. 12 to 14. At this juncture,it should also be added that in the step shown in FIG. 71, the bumpelectrode (second protruding electrode) 81 is formed by plating with theSOI substrate layer 190 being used as the cathode.

In a step shown in FIG. 72, the supporting member 32 is bonded to thesurface flush with the back surface of the second semiconductorsubstrate 2 of the second semiconductor element 6 by interposingtherebetween the adhesive layer 33. Thereafter, only the semiconductorsubstrate matrix 190 remaining on the back surface of the SOI substrate1 (191) is removed by etching until the bottom portion of the throughelectrode 12 is exposed on the back surface of the first semiconductorsubstrate 1 (191).

At this time, the extremely thin semiconductor film is formed on theburied insulation film 191 with the semiconductor substrate matrix 190having ultimately been removed. Thus, by properly designing thesemiconductor circuit and carrying out the process of fabricating thesemiconductor circuit, the process of depositing the insulation film 30and the process of removing the bottom portion of the hole (12) inprecedence to the formation of the connecting conductor 9 can be sparedwhile preventing short-circuit from being formed between thesemiconductor substrate 1 (191) and the through electrode 12.

Further, in the formation of the through electrode 12 by electroplating,no especial step is required because the semiconductor substrate matrix190 which is not yet removed at this time point can be used as theplating electrode.

Furthermore, for the removal of the semiconductor substrate matrix byetching after the semiconductor substrate matrix has been ground,control of the etching rate is rendered unnecessary because the removalis automatically stopped at the buried oxide film (insulation film) 191.

As is apparent from the above, since the SOI substrate has the buriedinsulation film 191 formed in advance, there is no necessity of formingthe insulation film. Thus, the semiconductor device enjoying enhancedelectrical stability and reliability can be realized.

Incidentally, the forgoing description has been made on the assumptionthat the first semiconductor substrate 1 employed in the semiconductordevices described hereinbefore in conjunction with the first tothirteenth embodiments is replaced by the SOI substrate. It shouldhowever be appreciated that in the semiconductor devices according tothe fourteenth to eighteenth embodiments of the invention, similarreplacement is possible.

Additionally, although it has been described that the so-called buriedoxide-type SOI substrate, i.e., the semiconductor substrate having theburied oxide film 191 buried or embedded therein is employed, aso-called bonded-type SOI substrate, i.e., the composite substrateformed by bonding at a high temperature a semiconductor substrate on thesurface of another semiconductor substrate formed previously with anoxide film, whereon one of the semiconductor substrates is ground to apredetermined thickness, may be employed.

Besides, although the SOI substrate is employed as the firstsemiconductor substrate, it should be understood that the semiconductordevice of the same structure capable of serving for the same functioncan be realized by forming an electrically conductive layer on a backsurface of a so-called thin film transistor (TFT) substrate in which athin film transistor (TFT) is formed on an insulation substrate, forminga hole which reaches the electrically conductive layer and then forminga through electrode by plating, using the electrically conductive layeras the electrode and eliminating finally the electrically conductivelayer.

Embodiment 20

FIG. 73 is a sectional view showing a semiconductor device according toa twentieth embodiment of the present invention. In this figure, theconstituents or components similar to those described previously inconjunction with the first to nineteenth embodiments of the invention byreference to FIGS. 1 to 72 are denoted by like reference symbols, andrepeated description in detail of these components will be omitted.

Referring to FIG. 73, a wiring conductor layer 150 is formed on thesurface of the buried insulation film 191 which is exposed in backsurface of the first semiconductor element 5 formed in the firstsemiconductor substrate.

The wiring conductor layer 150 mentioned above is used for rewiring byresorting to a method well known in the semiconductor processtechnology. The rewiring can easily be realized by making use of theinsulation film 191.

Further, upon grinding the back surface of the semiconductor substratematrix 190 of the SOI substrate, the grinding is carried out till theback surface of the buried insulation film 191 (back surface of theinsulation film 191) is exposed with the semiconductor substrate matrix190 being completely eliminated without interrupting the grinding at thetime point the through electrode bottom portion is exposed. Then, thesurface of the buried insulation film 191 having no offset portions canbe obtained, whereby the wiring conductor layer 150 can be formed withmore ease.

A protruding electrode 80 may be formed in the wiring conductor layer150.

Embodiment 21

FIGS. 74 and 75 are sectional views showing a semiconductor deviceaccording to a twenty-first embodiment of the present invention. Inthese figures, the constituents or components similar to those describedpreviously in conjunction with the first to twentieth embodiments of theinvention by reference to FIGS. 1 to 73 are denoted by like referencesymbols, and repeated description in detail of these components isomitted.

In FIG. 74, there is shown a semiconductor device which corresponds to acombination of the semiconductor devices according to the fourth andnineteenth embodiments of the invention.

On the other hand, FIG. 75 shows a semiconductor device corresponding toa combination of the semiconductor devices according to the fourth andtwentieth embodiments of the invention.

In the semiconductor device shown in FIG. 74, the back surface of theburied oxide film (insulation film) 191 of the SOI substrate 1 can bemade use of as the first external terminal without providing the wiringconductor, the number of terminals can be increased with shortesttransmission paths.

Further, by employing the SOI substrate 1, the overall thickness of theextremely thin semiconductor layer in which the first semiconductorcircuit 3 is formed and the buried oxide film 191 is still considerablysmall. Thus, the etching depth for forming the holes is extremely small.Owing to this feature, the conductive material for the hole can beburied upon forming the connecting conductor 9 without resorting to theplating process. In this way, a large number of small terminals can beformed by a much simplified method.

Incidentally, protruding electrodes 80 may be provided by forming thewiring conductor layers 150 on the back surface of the SOI substrate 1,as shown in FIG. 75.

Embodiment 22

FIGS. 76 and 77 are sectional views showing a semiconductor devicesaccording to twenty-second embodiment of the present invention. In thesefigures, the constituents or components similar to those describedpreviously in conjunction with the first to twenty-first embodiments ofthe invention by reference to FIGS. 1 to 75 are denoted by likereference symbols, and repeated description in detail of thesecomponents will be omitted.

In the semiconductor device shown in FIG. 76, an SOI substrate or aninsulation substrate having the thin film transistor (TFT) formedthereon is employed as the second semiconductor substrate 2 of thesecond semiconductor element 6.

In the semiconductor device shown in FIG. 77, the SOI substrate isemployed as the second semiconductor substrate 2 of the semiconductordevice 6 shown in FIG. 74.

Thus, in the semiconductor devices according to the first to thirteenthembodiments of the invention and the semiconductor devices in which theSOI substrate is employed as the first semiconductor substrate 1, it ispossible to improve the electrical stability and the chemical/mechanicalwithstanding capability to thereby enhance the reliability with ease,similarly to the semiconductor device according to the fourteenthembodiment in which the back surface of the second semiconductor element6 is coated with the insulation material (insulation film), without needfor forming the insulation film on the back surface of the secondsemiconductor element 6 by using the substrate having the insulationlayer deposited thereon in advance.

In the method of manufacturing the semiconductor devices describedabove, the SOI substrate or alternatively the insulation substratehaving the thin film transistor (TFT) formed thereon is employed as thesecond semiconductor element 6 in the step described hereinbefore inconjunction with the third embodiment by reference to FIG. 12.

Further, in the step shown in FIG. 14, the grinding is carried out untilthe back surface of the second semiconductor element 6 is exposed.

Embodiment 23

FIGS. 78 and 79 are sectional views showing semiconductor devicesaccording to a twenty-third embodiment of the present invention. Inthese figures, the constituents or components similar to those describedpreviously in conjunction with the first to twenty-second embodiments ofthe invention by reference to FIGS. 1 to 77 are denoted by likereference symbols, and repeated description in detail of thesecomponents will be omitted.

In the semiconductor device shown in FIG. 78, a wiring conductor layer150 is formed on the surface flush with the back surface of the secondsemiconductor element 6 in the semiconductor device shown in FIG. 76,wherein the back surface of the wiring conductor layer 150 is made useof as regions for disposition of external terminals.

Bump electrode (second protruding electrode 81) may be formed on the topsurface of the wiring conductor layer 150, as in the case of thesemiconductor device shown in FIG. 78.

Thus, in the semiconductor devices according to the instant embodimentof the invention, the integration density can be enhanced with thenumber of the connecting terminals being increased without need foradditional step of forming the insulation film.

Similarly, the wiring conductor layer 150 may additionally be formed onthe surface extending in flush with the back surface of the firstsemiconductor element 5 in the semiconductor device shown in FIG. 77, ascan be seen in FIG. 79.

Embodiment 24

FIGS. 80 and 81 are sectional views showing stack type semiconductordevices according to a twenty-fourth embodiment of the presentinvention. In these figures, the components similar to those describedpreviously in conjunction with the first to twenty-third embodiments ofthe invention by reference to FIGS. 1 to 79 are denoted by likereference symbols, and repeated description in detail of thesecomponents is omitted.

In the semiconductor device shown in FIG. 80, a third semiconductorelement generally denoted by 240 is stacked with interposition of theadditional wiring conductor (wiring conductor layer 150) formed on theback surface of the second semiconductor element 6 of the semiconductordevice shown in FIG. 46. The third semiconductor element 240 isimplemented in the same structure as the second semiconductor element 6.Incidentally, reference numeral 241 denotes a semiconductor circuit and242 denotes an electrode.

In the case of the semiconductor device shown in FIG. 81, a thirdsemiconductor element 240 and a fourth semiconductor element 244 eachformed in an SOI substrate or thin film transistor (TFT) substrate areserially stacked with interposition of the additional wiring conductors(wiring conductor layer 150) formed on the back surface of the secondsemiconductor element 6 of the semiconductor device shown in FIG. 76.The third and fourth semiconductor elements 240 and 244 are eachrealized in the same structure as the second semiconductor element 6.Incidentally, in FIG. 81, reference numerals 245 and 241 denotesemiconductor circuits, respectively, and numeral 246 and 242 denoteelectrodes, respectively. In the semiconductor device shown in FIG. 81,bump electrodes (protruding electrodes 80, 81) are formed on the top andback surfaces, respectively.

In this manner, a plurality of semiconductor elements can be stacked orlaminated by repeating the same structure, whereby the integrationdensity can be enhanced.

Embodiment 25

FIGS. 82 to 86 are views for illustrating processes involved in thesemiconductor device manufacturing method according to the twenty-fifthembodiment of the present invention. In FIGS. 82 to 86, the componentssimilar to those described previously in conjunction with the first totwenty-fourth embodiments of the invention by reference to FIGS. 1 to 81are denoted by like reference symbols, and repeated description indetail of these components is omitted.

In FIGS. 82 to 86, there is illustrated a method of manufacturing thesemiconductor device according to the twenty-fourth embodiment of theinvention. More specifically, in the additional wiring conductor formingprocess described hereinbefore in conjunction with the sixteenth toeighteenth embodiments or twenty-second or twenty-third embodiments,terminals are formed at the positions where the bump electrodes are tobe formed on the third semiconductor element 240 and connected to thebump electrodes. Subsequently, the method described in conjunction withthe sixteenth to eighteenth embodiments is repetitionally carried out tothereby extend the through electrode 12 upwardly.

In the step shown in FIG. 82, the first semiconductor element 5 and thesecond semiconductor element 6 are each formed by using the SOIsubstrate.

In the step shown in FIG. 83, the insulation layer on the back surfaceof the second semiconductor substrate and the top end portion of thethrough electrode top portion is exposed by grinding.

In the step shown in FIG. 84, the additional wiring conductor 150 isdeposited on the second semiconductor substrate 2, whereon thephotoresist layer 31 having an opening in which the through electrode isto be formed is formed. In succession, the through electrode 12 isformed by electroplating. In that case, the first semiconductorsubstrate 1 being used as the cathode.

In the step shown in FIG. 85, the photoresist (layer?) 31 is removed,and then the third semiconductor element 240 including the SOI substrateis disposed to be subsequently covered with the insulation material 13.

In the step shown in FIG. 86, the top end portion of the extendedthrough electrode 12 and the insulation layer of the secondsemiconductor substrate are exposed through the grinding processsimilarly to the steps described previously by reference to FIG. 86.

Further, a fourth semiconductor element et seq. may be stacked byrepetitively carrying out the process shown in FIGS. 82 to 86.

Finally, the back surface of the first semiconductor substrate is groundto expose the bottom portion of the through electrode 12. At this stage,the bump electrodes (protruding electrodes) may be formed on the backsurface.

Extension of the through electrode 12 can be realized similarly throughthe processes described hereinbefore in conjunction with the seventeenthand eighteenth embodiments of the invention.

By the method described above, the semiconductor device can bemanufactured with an enhanced integration density.

Embodiment 26

FIG. 87 is a sectional view showing an integrated semiconductor devicestack according to a twenty-sixth embodiment of the present invention.In this figure, the constituents or components similar to thosedescribed previously in conjunction with the first to twenty-fifthembodiments of the invention by reference to FIGS. 1 to 86 are denotedby like reference symbols, and repeated description in detail of thesecomponents is omitted.

FIG. 87 shows a stack-type integrated semiconductor device of acomposite structure realized by stacking the semiconductor structuresdescribed hereinbefore in conjunction with the first to twenty-fifthembodiments in combination. More specifically, the semiconductor devicenow concerned is implemented by stacking semiconductor devices 260according to the eighth embodiment of the present invention shown inFIG. 33 and the semiconductor device 261 according to the fifteenthembodiment shown in FIG. 55.

In the semiconductor device stack shown in FIG. 87, two semiconductordevices 260 shown in FIG. 33 and one semiconductor device shown in FIG.55 are employed. It goes however without saying that a given number ofany semiconductor devices described hereinbefore in conjunction with thefirst to twenty-fifth embodiments may be stacked in a given order. Thus,a semiconductor device stack structure of an extremely large scale canbe realized.

Embodiment 27

FIGS. 88 and 89 are sectional views showing an array type semiconductordevice (which may also be referred to as the semiconductor device array)according to a twenty-seventh embodiment of the present invention. Inthese figures, the constituents or components similar to those describedpreviously in conjunction with the first to twenty-sixth embodiments ofthe invention by reference to FIGS. 1 to 87 are denoted by likereference symbols, and repeated description in detail of thesecomponents is omitted.

FIG. 88 shows an array type semiconductor device implemented in the formof a semiconductor module in which a plurality of second semiconductorelements 6 are mounted on a single first semiconductor substrate in aplanar array.

On the other hand, in the array type semiconductor device shown in FIG.89, a group of first semiconductor circuits are formed on a singlesemiconductor substrate independently of one another, and secondsemiconductor elements are disposed on the first semiconductor circuits,respectively. Thus, the semiconductor device shown in FIGS. 1, 3 andothers can be obtained by cutting the structure shown in FIG. 89 atlocations indicated by “A”, respectively.

The semiconductor device of this type can be manufactured according tothe method described hereinbefore in conjunction with the thirdembodiment of the invention. Thus, integration of a large scale can berealized.

Embodiment 28

FIG. 90 is a sectional view showing a composite type semiconductordevice structure according to a twenty-eighth embodiment of the presentinvention.

In the composite type semiconductor device structure shown in FIG. 90, agroup of third semiconductor elements generally denoted by numeral 291are stacked on the semiconductor module 290 described above inconjunction with the twenty-seventh embodiment by adopting the stackingstructure described previously in conjunction with the twenty-fifthembodiment. Thus, the composite type semiconductor module of a greaterscale can be realized by combining the planar array of the semiconductorelements with the stacked array thereof.

Embodiment 29

FIG. 91 is a sectional view showing a composite type semiconductordevice structure according to a twenty-ninth embodiment of the presentinvention.

In the structure shown in FIG. 91, the first semiconductor substrate 1of the semiconductor module having the connecting terminals exposed onthe back surface as described previously in conjunction with thetwenty-seventh and twenty-eighth embodiments is connected with thesemiconductor device stacks (composite stacked structures shown in FIGS.42 to 45 and FIG. 87) including the semiconductor devices describedhereinbefore in conjunction with the first to tenth embodiments or thesemiconductor devices according to the eleventh to thirteenthembodiments and the semiconductor device according to twenty-sixthembodiment. With this structure, the composite semiconductor module ofan extremely large scale can be realized.

Embodiment 30

FIG. 92 is a sectional view showing a semiconductor device according toa thirtieth embodiment of the present invention. In this figure, theconstituents or components similar to those described previously inconjunction with the first to twenty-ninth embodiments of the inventionby reference to FIGS. 1 to 91 are denoted by like reference symbols, andrepeated description in detail of these components is omitted.

In the structure shown in FIG. 92, the first semiconductor circuit 3 isnot formed on the first semiconductor substrate 1. Thus, with thisstructure, the integration density as realized is inferior to that ofthe semiconductor devices described so far. However, because thestructure is simple and because the manufacturing process is nottime-consuming and simple, there can be realized very inexpensivesemiconductor device with high yield.

At this juncture, it should be added that similar structure can berealized even in the case where a metal board is employed in place ofthe first semiconductor substrate 1.

Further, by using the etching process in combination with theback-surface grinding, the semiconductor substrate matrix and the metalboard of the first semiconductor substrate may all be removed.

Many modifications and variations of the present invention are possiblein the light of the above techniques. It is therefore to be understoodthat within the scope of the appended claims, the invention may bepracticed otherwise than as specifically described.

1. A semiconductor device, comprising: first and second semiconductorsubstrates having respective opposite surfaces disposed in opposition toeach other; a first semiconductor element formed in said oppositesurface of said first semiconductor substrate and comprised of a firstsemiconductor circuit and a first electrode; a second semiconductorelement formed in said opposite surface of said second semiconductorsubstrate and comprised of a second semiconductor circuit and a secondelectrode; a first wiring conductor layer formed of an electricallyconductive material and interposed between said first and secondelectrodes; and a through electrode extending through said firstsemiconductor substrate and connected to said first and secondelectrodes through the medium of said first wiring conductor layer,wherein said second semiconductor substrate is disposed above said firstsemiconductor substrate and disposed on a lateral side of said throughelectrode, being distanced therefrom; wherein lateral surface of saidthrough electrode projecting from said first semiconductor substrate andlateral surface of said second semiconductor element are coated with aninsulation material layer; wherein said through electrode has one endportion exposed from a back surface of said first semiconductorsubstrate to serve as a first external terminal; and wherein saidthrough electrode has the other end portion positioned at a same heightas a back surface of said second semiconductor substrate and exposedfrom said insulation material layer to serve as a second externaltenninal.
 2. The semiconductor device according to claim 1, wherein saidsemiconductor device further includes a first additional externalterminal exposed from a back surface of said first semiconductorsubstrate in a region in which said second semiconductor substrate ismounted.
 3. The semiconductor device according to claim 1, wherein theback surface of said second semiconductor substrate is coated with aninsulation material.
 4. The semiconductor device according to claim 3,wherein said semiconductor device includes a second wiring conductorlayer of an electrically conductive material deposited on a surface ofthe insulation material of said first and second semiconductorsubstrates and an exposed surface of said second external terminal, andwherein said second wiring conductor layer is connected to said throughelectrode at a portion thereof which is exposed as said second externalterminal.
 5. The semiconductor device according to claim 1, wherein anelement interconnecting protrusion electrode is provided between saidfirst electrode and said second electrode, and wherein said firstsemiconductor element and said second semiconductor element areinterconnected through the medium of said element interconnectingprotrusion electrode.
 6. The semiconductor device according to claim 1,wherein a device connecting protrusion electrode projecting from theexposed surface of said through electrode is provided in associationwith at least one of said first external terminal and said secondexternal terminal, and wherein said device interconnecting protrusionelectrode is employed as an external terminal.
 7. The semiconductordevice according to claim 1, wherein an SOI (silicon oxide insulation)substrate is employed for forming said first semiconductor substrate,and wherein an SOI insulation film is exposed as the back surface ofsaid first semiconductor substrate.
 8. The semiconductor deviceaccording to claim 7, wherein a third wiring conductor layer isdeposited on said SOI insulation film of said first semiconductorsubstrate, said third wiring conductor layer being connected to saidfirst external terminal.
 9. The semiconductor device according to claim1, wherein an SOI (silicon oxide insulation) substrate is employed assaid second semiconductor substrate, and wherein said SOI substrateincludes an exposed SOI insulation film formed in the back surface ofsaid second semiconductor substrate.
 10. The semiconductor deviceaccording to claim 1, wherein a plurality of the semiconductor devicesset forth in claim 1 is interconnected through the medium of said firstexternal terminal and/or said second external terminal.
 11. Thesemiconductor device according to claim 10, wherein said semiconductordevice further comprises a third semiconductor substrate mounted on saidsecond semiconductor substrate; and a third semiconductor element formedin said third semiconductor substrate and comprised of a thirdsemiconductor circuit and a third electrode, wherein said thirdelectrode is connected to said second external terminal, and whereinlateral surface of said third semiconductor element and a surface ofsaid third semiconductor substrate in which said third semiconductorcircuit is formed are coated with an insulating material.
 12. Thesemiconductor device according to claim 1, wherein said throughelectrodes and said first semiconductor circuits are formed in pairs,respectively, in said first semiconductor substrate, wherein said secondsemiconductor elements are disposed with said second electrodes beingconnected to the first electrodes of said plurality of firstsemiconductor circuit, respectively; and wherein the surfaces of saidfirst and second semiconductor substrate in which said first and secondsemiconductor circuits are formed, respectively, lateral surfaces ofsaid second semiconductor substrates, and lateral surfaces of saidthrough electrodes, respectively, are coated with an insulation materialto thereby implement an integral planar array structure on a singleboard constituted by said first semiconductor substrate.
 13. Thesemiconductor device according to claim 12, wherein a plurality ofsemiconductor elements are stacked in at least one of said semiconductordevices connected to the first electrodes of said plurality of firstsemiconductor circuits.
 14. The semiconductor device according to claim1, wherein thickness of said first semiconductor substrate does notexceed 20 μm.